Few medications have attracted more attention from the public and federal agencies than those prescribed for attention deficit hyperactivity disorder (ADHD).

Millions of children and adults suffer from the disorder, yet the most common medications are feared to have powerful cardiovascular side effects.Despite this, several conflicting studies and reports failed to explain the risk posed by ADHD drugs.

Now, a large federal study of young- and middle-aged adults confirms no link between heart-related complications and ADHD stimulant medications. The report, published in the Journal of the American Medical Association (JAMA), should provide a measure of comfort for those who benefit from ADHD drugs but are concerned about serious side effects.The study follows similar findings reported in children published earlier this year in Current Psychiatry Report.

Nearly 50 million prescriptions were written for ADHD drugs in 2010, up 21% from 2008.The majority of these were for children and teens. However, an ever-increasing percentage was dispensed for patients aged 20 and older – now up to 46% of all ADHD prescriptions.

Stimulant-class medications include methylphenidate (Ritalin, Methylin, Metadate, Daytrana, Focalin, and Concerta), amphetamines (Adderall, Dexedrine, and Vyvanse). Atomoxetine (Strattera), a popular non-stimulant alternative for treatment of ADHD, hasn’t been linked with the side effects attributed to the stimulant class of medications.

In 2011, a report from the Food and Drug Administration's Drug Safety and Risk Management Advisory Committee noted that cardiac arrest, myocardial infarction and sudden unexplained death were among the top 50 adverse events reported after use of ADHD stimulant medications. One 2009 study, published in the American Journal of Psychiatry, suggested markedly elevated risks of sudden cardiac death among children taking these prescription drugs. However, other studies failed to clearly establish a relationship to severe cardiovascular complications.

In 2006, concerns about cardiovascular side effects led an FDA advisory committee to propose that a so-called black box warning label concerning sudden death be placed on psychostimulant medications. Some psychostimulants were withdrawn from the market in Canada and the American College of Cardiology recommended considering routine EKGs prior to initiating psychostimulant therapy.

Pemoline, another central nervous system stimulant, was taken off the U.S. market in 2005 after multiple liver toxicity reports.

According to the Centers for Disease Control, in 2007 there were 4.5 million children ages 3-17 with ADHD.Boys were found more than twice as likely to have ADHD: 11% vs. 4% of girls. Children with fair or poor health were nearly three times more likely to have ADHD than healthy children. Less healthy children were thought to be potentially more susceptible to the side effects of powerful stimulant drugs.

Approximately 4.5% of adults between the ages of 18 and 44 are estimated to have ADHD symptoms and disabilities.The most commonly used ADHD medications, psychostimulants and atomoxetine, are known to increase blood pressure and heart rate which, in turn, have been linked with serious cardiovascular events such as stroke and heart attacks.

While the JAMA study provides reassurance about the safety profile of psychostimulant drugs, all patients treated with ADHD medications should continue to be monitored for changes in heart rate or blood pressure, along with other side effects such as weight loss, increased anxiety and sleep disturbances.

Check with your doctor but, according to the FDA, patients with serious cardiovascular disease whose condition may be exacerbated by elevated pulse or blood pressure shouldn’t be administered ADHD stimulant drug therapy.